SYNTHESIS OF SOME NONIONIC POLYURETHANE SURFACTANTS AND EVALUATION OF THEIR EFFECTS IN IMPROVING THE PROPERTIES OF WATER BASE MUD

Abstract

The procedures and the methodology of this study can be summarized in the following topics: - The experimental protocol of the study is divided into two sections, the first is synthesis of different nonionic polyurethane additives; the second is the evaluation of the different polyurethanes and their corresponding esters (oleates and linoleates) as rheological modifiers and filtrate loss reducers in water base drilling fluids. 1. Synthesis of the polymeric additives a- Toluene diisocyanate (TDI) was reacted by polyethylene glycol with different molecular weight (4000, 6000, 10000 and 20000 g mole-1) in appropriate amount of suitable solvent and catalyst. b- The obtained nonionic polyurethane polymers were characterized by FTIR spectroscopy. The formation of the nonionic polyurethane polymer was confirmed by the appearance of IR absorption band at 1724 cm-1 corresponding to (C=O) group of the formed ester in urethane and the disappearance of the isocyanate group at 2100 cm-1 IR absorption band of the molecular weights of the obtained polymers were determined by gas chromatography measurements. The chemical structures of the synthesized compounds were confirmed to have the following chemical structure. Polyurethanes (PU 4, 6, 10 and 20), where PU4 = PU4000 g/mole, PU6 = PU6000 g/mole, PU10 = PU10000 g/mole and PU20 = PU20000 g/mole.

c- The targeted compounds were synthesized by reaction of the different nonionic polyurethane polymers and two fatty acids namely: oleic and linoleic acids in equimolar ratio of (1:1). d- The chemical structure of the synthesized fatty esters of the nonionic polymers was characterized by FTIR spectroscopy. The formation of the ester linkage between the polymers and the fatty acids was assigned at 1728 cm-1. The synthesized compounds were confirmed to have the following chemical structure: -

Polyurethanes esters (PU4O, PU6O, PU10O, PU20O, PU4L, PU6L, PU10L and PU20L), where PU4O = 4000O g/mole, PU6O = PU6000O g/mole, PU10O=PU10000O g/mole and PU20O = PU20000O g/mole, PU4L = 4000L g/mole, PU6L = PU6000L g/mole, PU10L = PU10000L g/mole and PU20L= PU20000L g/mole.

e- The synthesized water soluble polyurethane surfactants and their corresponding esters (oleates and linoleates) were applied in water base drilling fluids as rheological modifiers and filtrate loss controlling agents. 2. Evaluation of the synthesized additives The synthesized nonionic polyurethane polymers were evaluated as additives in water base drilling fluids during drilling wells operations to cover improvement of two main processes: - 1- Rheological properties (Apparent viscosity (AV), Plastic viscosity (PV), Yield Point (YP), Yield Point/Plastic viscosity (YP/PV), Gel strength (G10s and G10 min), Thixotropic properties) of drilling fluid which are required in providing most of functions of drilling fluids during drilling operations of different types of wells. 2- Improving impermeable film on and beneath the solids components of filter cake which accordingly help in controlling the filtrate loss.